This is a note to let you know that I've just added the patch titled MIPS: Fix watchpoint restoration to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-fix-watchpoint-restoration.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a7e89326b415b5d81c4b1016fd4a40db861eb58d Mon Sep 17 00:00:00 2001 From: James Hogan <james.hogan@xxxxxxxxxx> Date: Tue, 1 Mar 2016 22:19:36 +0000 Subject: MIPS: Fix watchpoint restoration From: James Hogan <james.hogan@xxxxxxxxxx> commit a7e89326b415b5d81c4b1016fd4a40db861eb58d upstream. Commit f51246efee2b ("MIPS: Get rid of finish_arch_switch().") moved the __restore_watch() call from finish_arch_switch() (i.e. after resume() returns) to before the resume() call in switch_to(). This results in watchpoints only being restored when a task is descheduled, preventing the watchpoints from being effective most of the time, except due to chance before the watchpoints are lazily removed. Fix the call sequence from switch_to() through to mips_install_watch_registers() to pass the task_struct pointer of the next task, instead of using current. This allows the watchpoints for the next (non-current) task to be restored without reintroducing finish_arch_switch(). Fixes: f51246efee2b ("MIPS: Get rid of finish_arch_switch().") Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx> Cc: Paul Burton <paul.burton@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Patchwork: https://patchwork.linux-mips.org/patch/12726/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/include/asm/switch_to.h | 2 +- arch/mips/include/asm/watch.h | 10 +++++----- arch/mips/kernel/pm.c | 2 +- arch/mips/kernel/watch.c | 5 ++--- 4 files changed, 9 insertions(+), 10 deletions(-) --- a/arch/mips/include/asm/switch_to.h +++ b/arch/mips/include/asm/switch_to.h @@ -105,7 +105,7 @@ do { \ __clear_software_ll_bit(); \ if (cpu_has_userlocal) \ write_c0_userlocal(task_thread_info(next)->tp_value); \ - __restore_watch(); \ + __restore_watch(next); \ (last) = resume(prev, next, task_thread_info(next)); \ } while (0) --- a/arch/mips/include/asm/watch.h +++ b/arch/mips/include/asm/watch.h @@ -12,21 +12,21 @@ #include <asm/mipsregs.h> -void mips_install_watch_registers(void); +void mips_install_watch_registers(struct task_struct *t); void mips_read_watch_registers(void); void mips_clear_watch_registers(void); void mips_probe_watch_registers(struct cpuinfo_mips *c); #ifdef CONFIG_HARDWARE_WATCHPOINTS -#define __restore_watch() do { \ +#define __restore_watch(task) do { \ if (unlikely(test_bit(TIF_LOAD_WATCH, \ - ¤t_thread_info()->flags))) { \ - mips_install_watch_registers(); \ + &task_thread_info(task)->flags))) { \ + mips_install_watch_registers(task); \ } \ } while (0) #else -#define __restore_watch() do {} while (0) +#define __restore_watch(task) do {} while (0) #endif #endif /* _ASM_WATCH_H */ --- a/arch/mips/kernel/pm.c +++ b/arch/mips/kernel/pm.c @@ -56,7 +56,7 @@ static void mips_cpu_restore(void) write_c0_userlocal(current_thread_info()->tp_value); /* Restore watch registers */ - __restore_watch(); + __restore_watch(current); } /** --- a/arch/mips/kernel/watch.c +++ b/arch/mips/kernel/watch.c @@ -15,10 +15,9 @@ * Install the watch registers for the current thread. A maximum of * four registers are installed although the machine may have more. */ -void mips_install_watch_registers(void) +void mips_install_watch_registers(struct task_struct *t) { - struct mips3264_watch_reg_state *watches = - ¤t->thread.watch.mips3264; + struct mips3264_watch_reg_state *watches = &t->thread.watch.mips3264; switch (current_cpu_data.watch_reg_use_cnt) { default: BUG(); Patches currently in stable-queue which might be from james.hogan@xxxxxxxxxx are queue-4.4/mips64-r6-r2-emulation-bugfix.patch queue-4.4/mips-fix-uapi-include-in-exported-asm-siginfo.h.patch queue-4.4/mips-disable-preemption-during-prctl-pr_set_fp_mode.patch queue-4.4/mips-fix-sigreturn-via-vdso-on-micromips-kernel.patch queue-4.4/mips-fix-siginfo.h-to-use-strict-posix-types.patch queue-4.4/mips-don-t-unwind-to-user-mode-with-eva.patch queue-4.4/mips-vdso-build-with-fno-strict-aliasing.patch queue-4.4/mips-fix-watchpoint-restoration.patch queue-4.4/mips-build-micromips-vdso-for-micromips-kernels.patch queue-4.4/mips-math-emu-fix-jalr-emulation-when-rd-0.patch queue-4.4/mips-fix-msa-ld_-st_-asm-macros-to-use-ptr_addu.patch queue-4.4/mips-avoid-using-unwind_stack-with-usermode.patch queue-4.4/mips-prevent-restoration-of-msa-context-in-non-msa-kernels.patch queue-4.4/mips-use-copy_s.fmt-rather-than-copy_u.fmt.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html